Determination of Response Factors for Analytes Detected during Migration Studies, Strategy and Internal Standard Selection for Risk Minimization

Migration studies are one of the few domains of pharmaceutical analysis employing wide-scope screening methodologies. The studies involve the detection of contaminants within pharmaceutical products that arise from the interaction between the formulation and materials. Requiring both qualitative and quantitative data, the studies are conducted using Liquid Chromatography or Gas Chromatography coupled to a mass spectrometer (LC-MS and GC-MS). While mass spectrometry allows wide-scope analyte detection and identification at the very low Analytical Evaluation Threshold (AET) levels used in these studies, MS detectors are far from "universal response" detectors. Regulation brings the application of uncertainty factors into the picture to limit the risk of potential analytes detected escaping report and further evaluation; however, whether the application of a default value can cover any or all relevant applications is still debatable. The current study evaluated the response of species usually detected in migration studies, generating a suitable representative sample, analyzing said species, and creating a strategy and evaluation mechanism for acceptable classification of the detected species. Incorporating novel methodologies, i.e., Design of Experiments (DoE) for Design Space generation, the LC-MS-based methodology is also evaluated for its robustness in changes performed.

Chemometrically Assisted Optimization of Pregabalin Fluorescent Derivatization Reaction with a Novel Xanthone Analogue and Validation of the Method for the Determination of Pregabalin in Bulk via a Plate Reader

Quantitation of chromophore-free analytes is always a challenge. To this purpose, derivatization of the analyte constitutes a common strategy, leading to a product with a strong signal. In the current study, a novel xanthone analogue was utilized for the first time for the derivatization of pregabalin, a model analyte with a primary amine moiety that lacks a chromophore. The fact that only the xanthene-based derivative, formed after the derivatization reaction fluoresces, enables avoiding its chromatographic separation from the reagent and thus reducing the analysis time of a series of samples in 1–2 min via a plate reader. The reaction conditions were optimized via a central composite design (CCD), with fluorescence signal as the measure of the yield. The following factors that affect the derivatization reaction were chosen: (a) temperature, (b) reaction time, and (c) triethylamine solution volume used to drive the reaction to completion. After the identification of the optimal conditions, the method was validated according to ICH guidelines, using a fluorescence plate reader for signal measurement (λex = 540, λem = 615 nm). Finally, the newly developed high-throughput method was applied to the determination of drug content in pregabalin bulk.

Neuroendocrine differentiation in castration-resistant prostate cancer: A case report

The most common type of prostate cancer is acinar adenocarcinoma, which is androgen-dependent and, therefore, treated with chemical or surgical castration and androgen receptor inhibition. However, the disease usually progresses to castration-resistant prostate cancer (CRPC). A neuroendocrine pattern is frequently observed in the cellular composition of CRPC, which is considered to emerge as an effect of androgen deprivation therapy. This is the case report of a 69-year-old patient with prostate adenocarcinoma, who, after an initial period of disease control with radiotherapy and antiandrogens, was diagnosed with CRPC with high levels of prostate-specific antigen (PSA), unresponsive to androgen inhibition, with accompanying lung and osseous metastases. Bronchial biopsy of the lung metastasis revealed infiltration by non-small-cell adenocarcinoma of prostatic origin with neuroendocrine characteristics. On somatostatin receptor scintigraphy with ^99mTc-octreotide, there was high uptake by almost all known lung and osseous metastases. The patient was subsequently treated with a combination of docetaxel and octreotide, and a partial response was observed 6 months later, with reduction of the PSA level and the size of the lung metastasis. The aim of the present study was to provide a clinical example of the previously demonstrated, in vitro and in vivo, synergistic antitumor activities of docetaxel and octreotide in cases of CRPC selected by means of histological confirmation of their neuroendocrine nature and somatostatin receptor scintigraphy.

Nuclear medicine techniques in Merkel cell carcinoma: A case report and review of the literature

Merkel cell carcinoma (MCC) is a rare and aggressive type of neuroendocrine cancer of the skin. It predominantly affects the elderly, with a predilection for the sun-exposed skin of the head and neck. Risk factors include immune-suppressing diseases, such as human immunodeficiency virus (HIV), chronic lymphocytic leukemia and multiple myeloma, organ transplantation, and the presence of the newly-identified Merkel cell polyomavirus (MCPyV). Diagnosis is based on pathological findings, primarily the immunohistochemical determination of cytokeratin 20 positivity. By contrast, staging relies on conventional imaging methods, such as ultrasonography, computed tomography (CT) and magnetic resonance imaging, and nuclear medicine techniques, such as sentinel lymph node scintigraphy, somatostatin receptor scintigraphy (SRS), and positron emission tomography (PET)/CT with ¹⁸F-fluorodeoxyglucose (FDG) or alternative radiopharmaceuticals. The treatment of MCC is primarily surgical, with possible adjuvant radiation, while the use of chemotherapy appears to be an alternative therapeutic option that is used only in specific cases. The present study describes the case of a 43-year-old HIV-positive Caucasian man with MCC located on the posterior surface of the left thigh, which was identified by cytological and histological examination of tissue sampled by fine needle aspiration and biopsy performed under CT. SRS demonstrated a high uptake of ¹¹¹In-diethylene triamine pentaacetic acid-octreotide at the affected site. Therefore, the lesion was surgically excised, and the patient received chemotherapy and adjuvant radiotherapy. Three months subsequent to treatment, the patient underwent a PET/CT scan with ¹⁸F-FDG that demonstrated uptake in the cervical lymph nodes and the area of the excised lesion. These findings indicated that the disease was in remission. The aim of the present study was to highlight the value and contribution of nuclear medicine in the diagnosis, staging and follow-up, using PET/CT, octreoscan and sentinel lymph node scintigraphy, of patients with MCC, as well as the therapeutic strategy of radiolabelled somatostatin analogue scintigraphy.

Imaging of coronary artery bypass grafts by computed tomography coronary angiography

In recent years, computed tomography coronary angiography is commonly performed as a follow-up examination after coronary artery bypass graft surgery. Coronary grafts owing to their minimal motion are well visualized by computed tomography coronary angiography, allowing radiologists to assess their patency noninvasively with very high diagnostic accuracy. The purpose of this pictorial essay is to provide an excellent overview of the anatomy and findings concerning coronary artery bypass grafts.

Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography

BACKGROUND

Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern.

PURPOSE

To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA.

MATERIAL AND METHODS

Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test.

RESULTS

Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR ≤65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed.

CONCLUSION

Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure.

Mixed tumor of the vagina: sonographic and magnetic resonance imaging findings

Mixed tumor of the vagina is a rare benign neoplasm that is composed of epithelial and mesenchymal cells. The majority of tumors are asymptomatic and simple tumor excision is curative. We report a case with pathological confirmation that was seen in a 42-year-old woman. On ultrasound examination the lesion appeared as an ovoid hypoechoic mass, 2.0 x 2.7 cm in size, arising from the lower third of the vagina. The lesion was well defined, solid and showed diffuse hypervascularity on color flow images. Magnetic resonance imaging of the pelvis showed a well-circumscribed ovoid mass (2.0 x 2.5 cm) on the left lateral vaginal wall. On T2-weighted images the mass appeared as a homogeneous hyperintense lesion, while on T1-weighted images it was difficult to discern the mass from the vaginal wall. After intravenous administration of gadolinium the mass showed progressively increasing homogeneous enhancement. The lesion was excised without complication and there was no evidence of recurrence at the 10-month follow-up.

Smoking among high school students

INTRODUCTION

There are no recent data on smoking habits of high-school students in Greece. The primary objective of the study was to determine these epidemiological factors.

METHODS

The smoking habits of 927 high-school students (471 boys and 456 girls), aged between 15-18 years, in four regions of a Greek area (the island of Cos), were examined. Study data were collected using a questionnaire.

RESULTS

It was found that 32.48% of boys and 27.19% of girls are smokers; 43.3% had started smoking before the age of 14. The mean age for starting smoking was 14.4 +/- 1.9 years for the boys and 14.9 +/- 1.6 years for the girls. As many as 22.8% of the students smoke 6 to 10 cigarettes per day and 21.5% 16 to 20 cigarettes per day; 40.2% reported that they smoke out of spite. Students reported that their parents are aware that their offspring smoke in a proportion of 36.7%. Social standards and parental example were found to be the main determinants for starting smoking. The majority of the students (95.2%) stated that they are aware of the hazards associated with smoking.

DISCUSSION

Our findings highlight the need for smoking control interventions aimed at young people. Smoking is a major, yet preventable cause of morbidity and mortality. For these reasons, we view that adolescents should be targeted with a well-planned integrated anti-smoking policy and not just an initiative for raising awareness of smoking hazards.

Primary intrapulmonary thymoma: A systematic review

AIM

This article reviews the literature on the clinical features, diagnosis and management of primary intrapulmonary thymoma.

METHODS

Medline, Embase and Cochrane Library searches were performed on all relevant Anglo-Saxon language articles. The search words included "primary pulmonary thymoma" and "intrapulmonary thymoma". Secondary references were obtained from key articles. Prognostic and treatment strategies were analyzed by the Kaplan-Meier method, comparisons between curves were made using log rank test.

RESULTS

The searches yielded 25 cases of primary intrapulmonary thymoma. Median follow-up was 9 months (1 day to 13 years). At follow-up, 14 patients were tumor free, one patient had a local recurrence 8 years after radiotherapy, one patient responded favorably to radiotherapy, six patients died and three patients were lost to follow-up. The presence of a paraneoplastic syndrome decreased survival (P=0.02), however, histological subgroup (P=0.216), clinical stage (P=0.63) and tumor size (P=0.288) did not affect survival. Survival in surgically managed patients was significantly better than in conservatively managed patients (P=0.039). Adjuvant radiotherapy did not provide any benefit (P=0.4).

CONCLUSION

Complete resection of primary intrapulmonary thymomas appears sufficient in non-malignant tumors. Because of the risk of late local recurrence, long-term regular clinical follow-up is warranted.

Spirituality and religion in terminally ill patients with cancer

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Background: The importance of spirituality and religion in coping with a terminal illness is becoming increasingly recognised. We aimed to assess the relation between spiritual well-being, religiosity, depression, and end-of-life despair in terminally-ill cancer patients. Methods: One hundred forty three terminally ill cancer patients with a life expectancy of less than 6 months were interviewed with a series of standardised instruments, including the FACIT Spiritual Well-Being Scale, a religiosity index similar to those used in previous research, the Hamilton depression rating scale, the Memorial Symptom Assessment Scale and the Duke-UNC Functional Social Support Questionnaire. Results: A strong negative association was observed between the FACIT Spiritual Well-Being scale and the HDRS, but no such relationship was found for religiosity. Similar patterns were observed for the FACIT subscales, finding a strong negative association between the meaning and peace subscale (which corresponds to the more existential aspects of spirituality) and HDRS scores, whereas a positive, albeit nonsignificant, association was observed for the faith subscale (which corresponds more closely to religiosity). Conclusions: These results suggest that the beneficial aspects of religion may be primarily those that relate to spiritual well-being rather than to religious practices per se. Spiritual well-being offers some protection against end-of-life despair in those for whom death is imminent. The area of spiritual work is fertile ground for further investigation, especially interventions aimed at improving spiritual health and general quality of life among terminally ill patients with cancer.

No significant financial relationships to disclose.

Vascular injury complicating lumbar disc surgery. A systematic review

OBJECTIVES

to review the literature concerning the early and late vascular complications of lumbar disc surgery.

METHODS

using the MEDLINE database, we reviewed all reports of vascular complications associated with surgical excision of a prolapsed disc via a posterior approach reported in the English literature since 1965.

RESULTS

we identified 98 cases of vascular complications for an incidence of 1-5 in 10000 disc operations. Early presentation is shock due to rupture of a large retroperitoneal vessel. Late complications include development of pseudoaneurysms and arteriovenous fistulas. Treatment of a vascular tear consisted mainly of primary suturing of the injured vessel. The preferred method for arteriovenous fistula and pseudoaneurysm repair was suturing from within the arterial lumen along with interposition grafting. Recently, endovascular techniques have been recommended, lowering the high morbidity and mortality related to conventional repair.

CONCLUSION

iatrogenic vascular injury during lumbar disc surgery, although rare, should be suspected if signs of circulatory instability are noted or if lumbar pain, leg oedema or high output cardiac failure develop months to years following such surgical procedures. However, these symptoms may arise during or immediately after surgery, requiring immediate intervention.

Treatment of postoperative bronchobiliary fistula by nasobiliary drainage

Bronchobiliary fistula (BBF) is a rare condition. It may present as a complication of echinococcal or amebic liver disease. Management of such a fistula can be very difficult and is often associated with a high rate of morbidity and mortality. We report the case of a 70-year-old woman who presented with a BBF after a one-stage operation for hydatid cysts of the liver and lung that were approached via thoracotomy and transdiaphragmatic incision. The cause of the BBF was an inflammatory collection in the residual liver cavity due to inadequate drainage. This collection eroded the sutured diaphragm, and because of the existing adhesions, it perforated directly into the bronchial system at the area of the previous cystectomy. Initially, endoscopic sphincterotomy was performed to achieve biliary decompression by equalizing intrabiliary and duodenal pressure, but no significant improvement was seen. Subsequently, nasobiliary drainage was instituted by means of an endoscopically inserted, nasobiliary catheter, which further reduced biliary pressure and facilitated biliary flow to the duodenum, as opposed to the fistulous tract. The fistula was successfully closed in a short time. This conservative method reduces the risks of reoperation. Therefore, it should be considered the treatment of choice in the management of bronchobiliary fistula.

Non-invasive myocardial iron assessment in thalassaemic patients. T2 relaxometry and magnetization transfer ratio measurements

PURPOSE

To compare T2 relaxometry and magnetization transfer ratio (MTR) measurements of myocardial tissue in normal volunteers and thalassaemic patients for assessment of the myocardial iron levels.

MATERIAL AND METHODS

All examinations were done on a 1 T MR system using a multi-echo spin-echo sequence with 8 echoes for T2 measurements and a gradient echo sequence for MTR measurements. Diastolic cardiac triggering was used in both sequences. Ten patients and 10 normal subjects were included in the study. T2 and MTR measurements were correlated with serum ferritin levels.

RESULTS

Regression analysis between T2 and MTR measurements and ferritin demonstrated a reversed linear relationship, (r=-0.932, p<0.05) and (r= -0.824, p<0.05), respectively. Mean T2 relaxation time and mean MTR of the normal subjects (57.95+/-4.9 ms and 43.70+/-3.3%) was significantly higher than that of the thalassaemic patients (38.8+/-6.2 ms and 26.40+/-6.1%) (p<0.01), respectively.

CONCLUSION

MTR measurements can be used to complement T2 measurements for non-invasive myocardial iron assessment.